1. Field of the Invention
This invention lies in the field of gas and smoke detectors.
More particularly it is concerned with a system which includes a sensor of a selected type, which is sensitive to a number of selected gases and to smoke. More particularly the detector system utilizes a plurality of sensors, in separate locations, and includes an electronic scanning means for selectively connecting each of the plurality of sensors to a single detector and meter, and stepping the detector sequentially to each of the sensors. Whenever the detector shows a value of meter current, or sensor current greater than the selected minimum, the stepping is stopped, so that the current, and a number can be displayed. The number corresponds to the particular sensor which is then connected to the detector. After a selected short period of time, the scanning means proceeds to contact each of the other sensors, and it will stop at each sensor that shows a greater than minimum sensor current.
2. Description of the Prior Art
In the prior art, there are many different types of sensors and sensor circuits illustrated.
All of the prior art sensors show a circuit which is adapted generally to a single sensor. If a plurality of such sensors are utilized, they include a separate control and display for each sensor, making for a very complex circuit, if there are a substantial number of sensors. Or they may connect all sensors in parallel to a single detector, which does not indicate which sensor is above threshold.
This invention is directed to a system for having a multiplicity of sensors, each of them in a separate location and measuring system, plus a scanning control which continuously scans the whole series of detectors looking for one that indicates a sensor current larger than a selected minimum value. When it finds such a sensor, scanning is stopped and the magnitude of sensor current is displayed, along with a number corresponding to that particular sensor and an alarm is sounded.